How to Calculate Your Water Bill

Paying for water and sewer services can be a significant expense for homeowners and renters alike. Understanding how your water bill is calculated can help you estimate costs, detect billing errors, and identify ways to reduce your water usage and save money. This guide explains the key factors that determine your water bill and provides a step-by-step walkthrough of how to calculate it yourself.

How Water Bills Are Calculated

Water bills consist of two main charges:

• Water usage charge – Based on the amount of water used, measured in hundred cubic feet (HCF) units. 1 HCF = 748 gallons.

• Sewer charge – A percentage of the water usage charge, meant to cover sewer system operating costs.

The total is the combined cost of the water and sewer charges. Here are the key details on how each part is determined:

Water Usage Charge

• Based on the number of HCFs used between meter readings.

• The meter measures consumption in cubic feet.

• The rate per HCF depends on your water provider but is commonly $4 – $5 per HCF.

• Usage is billed in HCF units. Consumption up to 1 HCF is rounded down and not billed. Consumption over 1 HCF is rounded up to the next HCF.

Sewer Charge

• Set as a percentage of the water usage charge, typically 120% – 150%.

• Covers the cost of operating and maintaining sewer infrastructure.

• Varies by municipality but does not change based on actual sewer usage.

How to Calculate Your Water Bill

Follow these steps to manually calculate your water bill based on your usage:

1. Get your water meter readings

• Locate your water meter. It is usually near the curb in front of your home.

• Note down the reading at the start and end of your billing period. Readings are in cubic feet.

• Subtract start reading from end reading to get total consumption.

2. Convert consumption to HCF

• Take the total cubic feet used and divide by 748 (the gallons in 1 HCF).

• Round up to the next whole HCF. This is your usage in HCF.

3. Multiply HCF used by the water rate

• Check your water provider’s current rate per HCF. For example, $4.49 per HCF.

• Multiply the HCF usage by the rate to get the water usage charge.

4. Calculate the sewer charge

• Sewer rates vary but are commonly 150% – 159% of the water rate.

• To get the sewer rate, take the water rate and multiply by the sewer percentage.

• Multiply the HCF usage by the sewer rate to get the sewer charge.

5. Add water and sewer charges

• Add together the water usage charge and the sewer charge.

• This is the total estimated cost of your water bill.

Water Bill Calculation Example

Let’s look at an example to demonstrate calculating a water bill:

• Start reading: 10,500 ft3
• End reading: 11,250 ft3
• Usage: 11,250 – 10,500 = 750 ft3
• 750 ft3 / 748 gallons per HCF = 1 HCF
• Water rate: $4.49 per HCF
• Sewer rate: 159% of water rate = $4.49 * 1.59 = $7.14 per HCF
• Water charge: 1 HCF * $4.49 = $4.49
• Sewer charge: 1 HCF * $7.14 = $7.14
• Total bill: $4.49 + $7.14 = $11.63

So for a usage of 750 cubic feet, or 1 HCF, the total estimated bill would be $11.63.

Tips for Reducing Your Water Bill

Here are some tips to lower your water usage and save money:

• Install low-flow showerheads and faucet aerators
• Fix any leaky faucets or running toilets
• Run full loads in the washing machine and dishwasher
• Shorten shower times
• Turn off the faucet while brushing teeth or shaving
• Water plants and lawn efficiently to avoid waste
• Look for rebates on water-efficient appliances and fixtures

Carefully monitoring your consumption and adopting water-saving habits can help shrink your water bill over time. Calculating your bill manually using meter readings is a great way to understand how your everyday usage impacts what you pay.